Protection for piping from elements is necessary in a number of applications. More specifically, pipe insulation, when not covered and protected, is susceptable to water and insect infiltration and deterioration. Other areas that require protection include wood posts, dock posts, etc., which when not covered, get dirty, wet, and consequently deteriorate.
When applying insulation to pipes, it is desirable to cover the end portion of the insulation at unions, valves, specialty fittings and the terminal ends of pipes. Finding a satisfactory way to cover the end portion of insulation has been a persistent and long term problem in the pipe insulation industry.
Raw ends of pipe insulation have been covered in various ways including cementing and canvasing, cementing and painting with a mastic coating, or covering the insulation with a thermoformed rigid PVC end cap. Although currently in use, none of these methods are entirely satisfactory for all applications because they do not stand up under high temperatures which may be generated by pipes carrying high temperature liquids and gases, i.e. hot water, steam, etc.
In cases of cementing and canvasing over or painting with mastic coating, the canvas and mastic coating materials tend to shrink and ultimately disintegrate when exposed to high pipe temperatures, weathering, or washdowns. Accordingly, these methods are unsuitable for high temperature applications. The end result of these methods has been deterioration of the pipe insulation; rusting of the pipe itself; loss of insulation value due to intrusion of moisture; and unattractive vermin or insect shelters in the case of cold piping.
End caps made of PVC have received much attention in recent years. These PVC end caps are shaped over molds made of two sections, each greater than a half circle. The thermoformed cover, therefore, has a slightly ovoid shape. After thermoforming, the PVC end cap is cut through one side and along the centerline of the base, but not through the side opposite to the cut side thereby forming two sections which are connected solely by the side wall which has not been cut. The end cap is then placed over the terminal portion of the insulation and the above-described sections are overlapped until the cover fits securely around the insulated pipe. A PVC end cap of this type has been manufactured by Proto Corp., Clearwater, Fla., and is more fully described in the 1986 product catalog of Proto Corp., page 6.
PVC end caps, like other methods of covering pipe insulation mentioned above, are limited because they have insufficient resistance to high temperatures. More specifically, PVC has a softening point of 150.degree. F to 165.degree. F, which is well below the temperature of high temperature liquids and gases flowing through the pipe. This makes use of PVC end caps for higher temperature applications impractical.
In light of the limitations of the cited methods, efforts have thus been made to form end caps out of metals, especially soft metals, such as aluminum. These materials offer resistance against deterioration at much higher temperatures than PVC and similar plastics.
However, the drawback to the use of metals is their inability to be drawn in oversized half-sections, as can be done for PVC, without the use of expensive individual dies. For this reason, metal end caps have been made by forming two separate and identical half sections. The two half-sections are then fitted around the insulated pipe and fastened by rivets, screws, etc. Metal end caps of this type and methods of manufacture are described in Holt, U.S. Pat. No. 276,044. Disadvantages associated with such methods include difficulty in fitting and fastening the two half-sections over pipes of small diameters, providing watertight seals and the difficulty for one person to install the cover about the pipe.